my-ms logo my-ms title
Nervous System Anatomy
Multiple sclerosis (MS) is a disease that has a direct effect on the central nervous system (CNS). Human anatomy in general covers every aspect of the human body, but in this case it will mostly focus on the human nervous system since that's where the damage from MS is and the symptoms originate from.

The symptoms of a nervous system problem depend on which area of the nervous system is involved and what is causing the problem. Nervous system problems may be degenerative (occurring slowly) and cause a gradual loss of function, or they may be acute (occurring suddenly) and cause life-threatening problems.

Looking at its basics, the human nervous system is a network of specialized cells that communicate information about a person's surroundings. It processes this information and causes reactions in other parts of the body. It's composed of neurons and other specialized cells called glia, that aid in the function of the neurons. This is looked at further in the microanatomy section.

The nervous system can basically be divided into the CNS and the peripheral nervous system (PNS). Neurons generate and conduct impulses between and within the two systems. The PNS is composed of sensory neurons and the neurons that connect them to the nerves, spinal cord, and brain, which make up the CNS. In response to stimuli, sensory neurons generate and propagate signals to the CNS which then processes and conducts signals back to the muscles and glands.

The neurons of the nervous systems are interconnected in complex arrangements and use electrochemical signals and neurotransmitters to transmit impulses from one neuron to the next. The interaction of the different neurons form neural circuits that regulate an organism's perception of the world and what is going on with its body, thus regulating its behavior.

The nerve pathway connecting the brain and spinal cord is made of upper motor neurons. The pathway between the spinal cord and muscles is made of lower motor neurons.

The nervous system enables basic motor skills and sensing. The traditional five senses (touch, taste, sight, smell, and hearing) are powered by the nervous system as are others such as equilibrioception (the sensing of gravity), nociception (the sensing of pain), and proprioception (the sensing of relative limb location and motion, as when touching the nose with closed eyes). Inhibition or disruption of these senses will retard basic motor skills.

After the nervous system is looked at, we then begin to look into the brain. Due to the many different systems in the brain, it's divided into four parts. A summary will introduce its basic functions and then we will expand upon that. You will be able to familiarize yourself with the many main segments of the brain all the way to the brainstem.

The final sections of anatomy that we will look into are the spine, spinal cord, and then the optic nerve. These are the final leg of the CNS and the final point of possible attack by MS. From the point beyond the spine, it becomes the PNS and out of the range of MS. Looking at the optic nerves, partial and even total vision lose may result from any damage.
General Anatomy Terminology
In anatomy, certain terms are used to denote orientation and body structure. Directional terms describe the positions of structures relative to other structures or locations in the body. Some of the terms are as follows:

Anterior or Ventral
Pertaining to the abdomen side or front, as opposed to the posterior, dorsal or back side (for example, the kneecap is located on the anterior side of the leg).
Coronal or Frontal Plane
A vertical plane running from side to side; divides the body or any of its parts into anterior and posterior portions.
Away from the exterior surface or further into the body, as opposed to superficial.
Away from or farthest from the trunk or the point or origin of a part, as opposed to proximal (for example, the hand is located at the distal end of the forearm).
Inferior or Caudal
Away from the head or lower, as opposed to superior or cranial (for example, the foot is part of the inferior extremity).
Below and to one side. Both inferior and lateral.
Away from the midline of the body (for example, the little toe is located at the lateral side of the foot).
Median or Horizontal Plane
A sagittal plane through the midline of the body; divides the body or any of its parts into right and left halves.
Toward the midline of the body (for example, the middle toe is located at the medial side of the foot).
Posterior or Dorsal
The back or behind, as opposed to the anterior or ventral (for example, the shoulder blades are located on the posterior side of the body).
Rotation of the forearm and hand so that the palm is down (and the corresponding movement of the foot and leg with the sole down), as opposed to supination.
With the front or ventral surface downward (lying face down), as opposed to supine.
Toward or nearest the trunk or the point of origin of a part (for example, the proximal end of the femur joins with the pelvic bone).
Sagittal or Lateral Plane
A vertical plane running from front to back; divides the body or any of its parts into right and left sides.
On the surface or shallow, as opposed to deep.
Superior or Cranial
Toward the head end of the body or upper, as opposed to inferior or caudal (for example, the hand is part of the superior extremity).
Rotation of the forearm and hand so that the palm is upward (and the corresponding movement of the foot and leg), as opposed to pronation.
With the back or dorsal surface downward (lying face up), as opposed to prone.
Transverse or Axial Plane
A horizontal plane passing through the standing body parallel to the ground; divides the body or any of its parts into upper and lower parts.
Upright, as opposed to horizontal.